Pyridine-2,6-dicarboxylic acid and 1,2-di-4-pyridylethylene react hydrothermally with nickel(II) nitrate, forming a metal-organic framework that forms a polycatenane-like structure through H-bonding interactions between water molecules and carboxylate O atoms with void spaces. Discrete acyclic trimeric and nonameric water clusters occupy the voids in the structures. X-ray powder diffraction and X-ray structure analysis have been used to characterize this compound. Crystal data for 1{(3dpeH(2))[Ni(pdc)(2)](3 center dot)15H(2)O}: monoclinic space group P2(1)/c, a = 24.730(5) angstrom, b = 19.895(2) angstrom, c = 17.257(4) angstrom, beta = 104.832(5)degrees, V = 8208(4) angstrom(3), Z = 4, R1 = 0.0429, wR2 = 0.1072, and S = 1.051.